Broadband multi-drop local network, interface and method for multimedia access

ABSTRACT

A broadband multi-drop local network, interface and method for multimedia access. A local network architecture include a wired bus coupleable directly to an external data network terminal and configured for carrying broadband packetized data traffic over a frequency spectrum uninterrupted by other defined data channels or services; and one or a plurality of network transceivers operable individually for coupling an addressable network device processing a defined class of information to the bus wherein each network appliance is configured for and further operable for providing communication interfacing of the class of information of each addressable network appliance with the packetized IP data traffic on the wired bus.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.10/341,148, filed Jan. 13, 2003, entitled “BROADBAND MULTI-DROP LOCALNETWORK, INTERFACE AND METHOD FOR MULTIMEDIA ACCESS,” which isincorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present disclosure relates in general to the field of networkcommunications technology, and more particularly, to a broadband,packet-based wireline local network technology for connecting a localservice provider or multiple service providers with one or more of avariety of electronic devices located in a user site.

BACKGROUND OF THE INVENTION

IP technology is beginning to migrate from the long haul networks intothe edge network carriers that are, in-turn, in the early stages ofoffering a variety of broadband services to business and residentialcustomers. Such broadband services are delivered at the user site viawideband coaxial cable or fiber optic cable, both of which arerelatively expensive compared to twisted-pair copper wire and requirecomplex and costly interface equipment to install devices thereto. Forsmall business and home networks, installation costs must be low, withhigh reliability or predictability of operation, both of which arecharacteristic of wired systems over short distances. Service providers,because of operational, hardware or time-to-market costs and highcapital investments required, are reluctant to make any major changes intheir outside plant infrastructure or equipment.

Present high speed data services are provided via the digital subscriberline (DSL) family of technologies such as ADSL, VDSL, HDSL, and IDSL. Asis well-known, present DSL services have limited bandwidth and datatransfer capabilities and are point-to-point services, i.e., service asingle device on a line or channel. The limitation of the point-to-pointaspect of these DSL delivery systems is that they do not allow formultiple devices or for the network to be directly connected orinterconnected. For example, an ADSL (Asymmetric DSL) link consists of aconnection from a DSL Access Multiplexer (DSLAM) located in a telephonecompany central office to an ADSL modem located in a residence orbusiness. If multiple computers at the location of the end user are tobe connected together and to the service provider, then the ADSL modemis tied to an additional network within the user site which provides thelink between the computers within the user site and to the ADSL modem.The ADSL modem, in turn, transfers data between the user site and thecentral office. An illustration of such a prior art network is providedin FIG. 6 described hereinbelow.

Referring now to FIG. 6 there is illustrated a typical example of aprior art local network as might be found in a small business orhome-user environment. A local network 670 is typically contained withina building or other structure and is coupled through a demarcation point682 and outside plant wiring 608 to an ADSL modem 606 in the facilitiesof an interconnect company 604 which provides access to the Internet 602or, alternatively, a wide-area network (WAN). From demarcation point682, the premises wiring 684 is coupled to an ADSL modem 612 whichdemodulates and converts incoming data signals to the data format usedby the illustrative Ethernet system utilized in the local network 670.In the Ethernet system, the modem output may be coupled via 10/100 MbpsEthernet link 614 to a router 616 and thence via link 618 to an Ethernethub 620 for distribution to individual terminals 610 a, 610 b, . . . 610n via links 622 connected to the hub 620. Alternatively, the function ofthe hub 620 could be achieved using a switch 620, as is well known inthe field.

Referring further to FIG. 6, it will also be appreciated that the priorart system shown therein has the disadvantage in that it requires acomplete local network 670—i.e., a secondary network coupled to thenetwork provided by the interconnect company 604—in order to link aplurality of devices to a single demarcation 682 of a small business orhome-use system as contained in a building. Further, in a typicalsecondary network such as an Ethernet system, the variety of devices towhich it may be connected is limited to computers and peripheralsthereto, and perhaps telephone equipment (not shown). Yet anotherdisadvantage is the limitation in data rate of the high speed linkconnected to the user site to 6 or 8 Mbps, which is not adequate for adigitized NTSC video signal plus required overhead of the high speedlink.

It is also characteristic of many of the existing broadband networktechnologies that they do not operate at data rates required forhandling multiple channels of video. For example, it is well known thata single channel of standard NTSC video requires 6 to 8 Mbps, and asingle channel of high definition (HDTV) video requires 16 to 20 Mbps,when digitized for transmission on a data link. Moreover, these datarates do not include the IP overhead required for digital transmissionwhich can add significantly to these figures. For example, approximately100 Mbps capability would be required to provide two channels ofdigitized HDTV simultaneously, one channel to each of two highdefinition television receivers. Thus, very high data rates are requiredfor providing multimedia services such as “video on demand” or “videobroadcasting” in order to ensure transfer of the data at the requiredpacket data rate. Of the existing technologies, VDSL(Very-high-data-rate DSL) and data cable most nearly approach thebandwidth requirements for this type of service; however, neither VDSL(which is limited to 30 MHz bandwidth) or IP-based data cableconfigurations provide multi-drop capability. Multi-drop capability isvery important when considering low-cost and high volume consumer orbusiness applications. Moreover, the increased cost and complexity ofexisting high speed data distribution technologies act as a barrierimpeding the rapid deployment of broadband services in small business orresidential applications.

A further aspect of data networks that must be addressed in anybroadband network handling real-time data traffic is the quality ofservice or QoS requirement. QoS, loosely defined, is another name forthe design specifications of a data and/or telecommunications network interms of traffic densities, call priorities, bit error rate (BER), delayand other parameters. QoS thus provides for configuring the network tohandle the anticipated traffic, giving consideration to sessionduration, data volume, priorities, the number of channels available,network traffic densities at peak times or average times, the allowablenumber of blocked access attempts, the rate of growth of data traffic,etc. In QoS these considerations are processed to enable the bestpossible utilization of resources of the network for both real-time andnon real-time data traffic in a variety of multimedia classes ofservices such as voice, audio/video data, interactive data,non-interactive data, etc. Properly applied, QoS is “engineered” intoeach portion of a network intended to carry real time data traffic.However, in the case of individual users or businesses having a need toimplement a small, high-speed local network on its side of thedemarcation to the premises, or its side of the curb-side “box,” in aneffort to provide real-time data communication in, out and within thenetwork, the risk of incompatible equipment and protocols is high, whichmay result in poor performance. This problem is especially acute whenreal-time data, high bandwidth/high data rates and a multiplicity ofdevices are present on the local network. Engineering QoS in a smalllocal network has heretofor been relatively expensive and additionallyrequired specialized knowledge. What is needed, therefore, is a way toprovide a local network within, e.g., one hundred meters (100 m) of thecurbside terminal, that provides an economical, simple-to-install anduse, network facility having full bandwidth, maximum data rates, hasmultidrop capability and has engineered QoS built-in to providemanagement of real-time data traffic.

SUMMARY OF THE INVENTION

There is disclosed herein a local network architecture, comprising awired bus coupleable directly to an external data network terminal andconfigured for carrying broadband packetized IP data traffic over anelectromagnetic spectrum uninterrupted by other defined data channels orservices; and one or a plurality of addressable network devices coupledrespectively to the wired bus via individual network transceivers,wherein each addressable network device is operable for processing adefined class of information to the bus and wherein each networkappliance is further configured for providing communication interfacingof the defined class of information of each addressable networkappliance with the packetized data traffic on the wired bus. In anotheraspect, the addressable network device comprises an addressable digitaldevice.

In a further aspect there is disclosed an interface transceiver foroperably coupling an addressable network device to a broadband wirelinelocal network, comprising a broadband modem, coupled via a physicalinterface to the broadband wireline local network, for demodulatingincoming packetized data from the network and modulating data outputfrom the addressable network device to form packetized data to thebroadband wireline local network; a network controller, coupled betweenthe broadband modem and a communication interface with the addressablenetwork device, for performing media access control (MAC) with errorcorrection, carrier sense multiple access with collision detection(CSMA/CD), and quality of service (QoS) affecting data traffic throughthe transceiver; and a communication processor, disposed integrally withthe communication interface with the addressable network device andconfigured to process data traffic between the network controller andthe addressable network device.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention and advantagesthereof may be acquired by referring to the following description, takenin conjunction with the accompanying drawings, in which like referencenumbers indicate like features, and wherein:

FIG. 1 illustrates a pictorial diagram of a first embodiment of abroadband multi-drop network in accordance with the present disclosure;

FIG. 2 illustrates a pictorial diagram of an alternate embodiment of anetwork in accordance with the present disclosure showing aconfiguration for optimum data rates;

FIG. 3 a is a graph illustrating the data rate and bandwidth utilizationof prior art technologies;

FIG. 3 b is a graph illustrating the data rate and bandwidth utilizationof the broadband multi-drop network technology of the presentdisclosure;

FIG. 4 is a block diagram showing the components of a broadbandmultidrop network interface and the components of a compatible telephoneset, and the interconnection thereof as are included in the illustrationof FIG. 2;

FIG. 5 is a block diagram showing the components of a broadbandmultidrop network transceiver;

FIG. 6 is a pictorial block diagram of a prior art local network system;

FIG. 7 illustrates a flow chart of one embodiment of the processingprovided in the QoS layer of FIG. 5;

FIG. 8 illustrates a diagrammatic view of a simplified multidropnetwork;

FIGS. 9 and 10 illustrate allocations of data traffic capabilities forthe network;

FIGS. 11 and 12 illustrate flowcharts for adding a node to the network;

FIG. 13 illustrates a simplified diagram of a network wherein each nodehas an update table;

FIG. 14 illustrates a simplified diagram of the network wherein acentral controller is provided with the update table;

FIGS. 15 and 16 illustrate flowcharts for accessing the network;

FIG. 17 illustrates a flowchart for adding a device to the network;

FIG. 18 illustrates a flowchart for determining data rate betweendevices; and

FIG. 19 illustrates a flowchart depicting the operation of controllingthe devices at which the data rate test is performed.

DETAILED DESCRIPTION OF THE INVENTION System Overview

For small local networks seeking to handle very high data rates, whereinthe data is transported in real time among multiple devices sharing thesame wideband medium, several technologies can be utilized to providethe simple but high performance broadband multidrop local network of thepresent disclosure. These include, for example, the physical (PHY) anddata link (e.g., media access control or MAC) layers of the OSI 7-layerreference network model, QoS requirements, and broadband modulationtechniques of wireless telecommunications.

The broadband multidrop local network to be described hereinbelow may bethought of as a full spectrum network system which includes thefollowing principal structural attributes: a wired bus carryingbroadband modulated RF data traffic, addressable network devices such asaddressable digital devices or appliances connected to the bus and anetwork interface within or associated with each connected device. Thebus in the present network, preferably constructed of twisted paircopper wire, carries no competing services or adjacent networks and,although the present wired bus has no restricted bandwidth segments, itis anticipated that power level limitations may be imposed by regulatoryagencies in certain bands. The bandwidth available is thus essentiallyunrestricted over the entire spectrum to at least several hundred MHzand beyond, allowing substantial volumes of traffic of correspondinglyhigh data rates. With current technologies, data rates extending intothe 500 to 1000 Mbps range may be readily utilized over reasonabledistances. This broadband wired bus, as thus configured, can carry anyamount of packetized data up to its capacity, among any number ofcompatible devices connected to the multidrop network.

When describing data communication over a bus or any type ofcommunication medium that handles packetized data, the concept of “datatraffic” must be understood. When a packet of data is assembled, it isassembled into a data packet of a defined “length” of data bits. Thetime that is required for this data packet to be transmitted is afunction of the rate at which data bits are transmitted, or the “bitrate.” Then there is the “packet rate” at which data must be transmittedfor a given application. For example, in a real time video application,there must be a certain number of packets of data transmitted in a givenframe or that frame can not be assembled at the receiving end. The wiredmedium or bus must first have a bandwidth that will handle the bit rate.Then a determination must be made whether the bit rate is fast enough totransmit at the packet rate. If so, then there is no problem meeting thedata transmission requirements for the device. However, if there is asharing arrangement with another device, then the packet rates for bothdevice will need to be accommodated. In order for both devices to beensured full access to the bus for transfer of data packets at therespective device packet rates, there must be a data traffic capabilityequaling the total of the two rates. Of course, this assumes that thebit rates are the same. If the bit rates are different, there must be anaccommodation made. There will then be required a defined amount of thedata traffic capabilities of the bus to be reserved for transmission ofpackets for any given device. By way of example, data traffic will bedefined as the number of data packets of any length that can betransmitted during a normalized unit of time. If a first device requiredforty percent of that normalized unit of time to ensure that all of itsdata packets would be accurately transmitted, then only sixty percentwould be left for other devices. It may be that the first devicetransmitted one hundred data packets during that forty percent and thatanother device transmitted only a single long packet over the last sixtypercent. Thus, the data traffic capability of this configuration wouldonly accommodate those two devices. It is noted that, if the seconddevice is not active, then sixty percent of the data trafficcapabilities of the bus will not be utilized. However, as will bedescribed hereinbelow, this is reserved for the sixty percent devicewhen such device needs that data traffic capability so as to allow it totransfer data packets at its full packet rate.

A wide variety of addressable network devices or addressable digitaldevices or appliances that are capable of communicating via high speeddata may be coupled together in the broadband multidrop local network ofthe present disclosure. Each such network device or appliance is coupleddirectly to the network bus via its own network interface—which includesa broadband transceiver—that is configured for “plug and play”installation by the user. Each network device may, for example, furtherinclude a label stating its data rate requirements in bits per secondand its requirements for packet transfer rate as one technique forimplementing network engineering, which provide information as to howmuch of the data traffic capabilities of the network will need to bereserved to ensure that all data packets can be transferred at rateddata rate and packet transfer rate. The user would merely add up thenumbers for all the connected network devices to determine the capacityutilization of the broadband multidrop local network. Other methods ofnetwork engineering to accomplish QoS requirements could include, butnot be limited to: (a) user notification by network attached devices,indicating that real-time throughput is being affected and that networkcongestion is occurring; and (b) user notification via attached networkdevices which obtain real-time throughput status and statistics via anetwork address associated with the service provider interface (i.e.,the network interface from the service provider that connects to thebroadband multidrop network). Since no separate modem is required tocouple the broadband multidrop local network to the interconnect serviceprovider, each digital data device or appliance is effectively directlyconnected to the interconnect service provider.

The network interface or broadband transceiver utilized in or associatedwith each network device or appliance is configured to provide highthroughput of real-time data at maximum packet transfer rate and presentminimal delay for non real-time data on the network. The system, in apreferred embodiment, employs a variant of orthogonal frequency divisionmultiplexing (OFDM), a specialized, packet-based, multiple subcarriermodulation scheme that emulates many of the attributes of spreadspectrum modulation, in combination with carrier sense multipleaccess/carrier detect (CSMA/CD) protocols to manage the data traffic onthe bus. Of course, the network architecture is not intended to belimited to the use of a multiple subcarrier modulation scheme and othermodulation schemes capable of transporting broadband packetized data ina wired network among a plurality of addressable devices may be used.Further, quality of service, QoS, is engineered into the system and maybe automated as an integral component in each network interface.

DESCRIPTION OF A FIRST EMBODIMENT

Referring now to FIG. 1, there is illustrated a first embodiment of abroadband multidrop local network 10 consistent with the presentdisclosure. Typically, network 10 may include a twisted-pair wire bus asexists in the outside plant 72 of a local interconnect company 70, suchas a telephone company local exchange carrier (LEC), cable companyoffice, or the like. Alternatively, the outside plant media couldconsist of coaxial cable in a cable network. It is also conceivable thatoptical versions of the embodiments of the present disclosure could bedeployed using optical fiber to transport the data in the network.

The broadband multidrop local network 10 of the present disclosureincludes the bus medium or wiring 84 within the end user site orbuilding 80 attached at demarcation point 82. A wired network carryingmodulated data traffic spanning the radio frequency range has theadvantage that a radio station site license, e.g. from a governmentauthority, is not required as it would be for some wirelesstechnologies. However, in most applications, compliance with RFemissions regulations may be required. A wired network as disclosedherein also has the ability to supply operating power such as DC voltageor low frequency AC voltage to each addressable digital device orappliance via the wired bus. While FIG. 1 illustrates a single locationor building 80, in other embodiments, network 10 could be connected to aplurality of locations. For example, a broadband multidrop local networkin a rural area, providing connection to multiple user sites inconjunction with compatible telephone systems, could be used to createseparate virtual lines to replace existing party lines. Using the singletwisted-pair outside plant and user site wiring, telephone systems andtelephone company equipment provided according to the present disclosuremay be economically implemented to provide separate calling facilitiesfor each location.

Referring further to FIG. 1, a building 80 contains a number ofaddressable network devices to be networked via interconnectingtwisted-pair wire 84 to the local interconnect company 70 via thedemarcation point 82 and the outside plant wiring 72. Devices that maybe used on the network 10 must be compatible with the networktransceiver 400 as shown in FIGS. 4 and 5 to be described hereinbelow.Such network devices may include, but are not limited to, computersystems 50 (a) . . . (n), telephone sets 52 (a) . . . (n), digital settop equipment 60, loop-start interface equipment 54, network-readyappliances 58, and security systems 64. Although not shown, othernetwork devices such as television sets, high fidelity audio equipment,DVD or VCR devices, security cameras, utility metering equipment,facsimile machines, etc., each having a built-in addressable networkinterface 400, may also be connected to the network 10.

The local interconnect company 70 distributes packetized IP traffic suchas the well-known Internet protocol (IP) for computers, or voice overInternet protocol (VOIP) for telephony, between various serviceproviders and the user site. For another example, IP-based televisionbroadcast service data distributed as streaming data can be routed toset top equipment 60 to be converted to video and audio signalscompatible with a television set 62. In this example, a singletelevision set 62 and set top equipment 60 are shown. In actualimplementations, one or more of each device may be used and thefunctions of television set 62 and set top equipment 60 may beintegrated into a single device. Another example is the routing ofdigitized and packetized telephony traffic between a telephone companyservice provider and at least one telephone set 52. The telephonecompany service provider may provide long distance capabilities, localcalling capabilities or a combination thereof. Still another exampleconsists of computers 50 (a) . . . (n) connected to the network 10. Thecomputers 50 (a) . . . (n) may intercommunicate using IP packets orcommunicate to and from at least one Internet service provider operatingthrough a local interconnect company 70. Yet another example is therouting of data traffic to communicate between the user site andsecurity services. The examples given are illustrative of the manypossible uses for the network of the present disclosure and are notintended to be limiting.

Network 10 as illustrated in FIG. 1 will typically have a lower datarate compared with the network 20 of FIG. 2, given the same modulationscheme and data transfer technology because of the length of twistedpair wiring in the outside plant, the lack of a separate interface,susceptibility to external electromagnetic fields, etc. or a combinationof the above. In an actual application of FIG. 1, the outside plantwiring 72 will likely be on the order of a few miles. Signal attenuationand reflections of the high frequencies occurring in the network 10 ofFIG. 1 as well as external interference impinging upon outside plantwiring will decrease data throughput proportionally. Thus, applicationsof the system of the present disclosure should best be used over shorterdistances in order to assure maximum data rates.

DESCRIPTION OF AN ALTERNATE EMBODIMENT

Referring now to FIG. 2, there is illustrated an alternate embodiment ofthe present disclosure directed to a very high speed data throughput.Very high speed data throughput has greater applicability invideo-on-demand and video distribution applications, very fast Internetaccess, video telephony, and the like. In FIG. 2, a building 80 containsat least one network device to be connected via twisted-pair wire 84 toLocal Interconnect Company 70 through demarcation point 82, thence via ashort run of outside plant wiring 76, through a broadband multidroplocal network interface 86, and finally through an outside plant opticalfiber or coaxial cable 74. Devices that may be used on the network 20must be compatible with the network interface 400 as will be describedhereinbelow in conjunction with FIGS. 4 and 5. Such network devices mayinclude, but are not limited to, computer systems 50 (a) . . . (n),telephone sets 52 (a) . . . (n), digital set top equipment 60,loop-start interface equipment 54, network-ready appliances 58, andsecurity systems 64. Although not shown, other network devices such astelevision sets, high fidelity audio equipment, DVD or VCR devices,security cameras, utility metering equipment, facsimile machines, etc.each having a built-in network interface 400 may also be connected tothe network 20. As described hereinabove, the local interconnect company70 distributes packetized IP traffic between various service providersand the user site.

By placing the broadband multidrop local network interface 86 (alsoreferred to herein as a multi-drop interface 86 or transceiver 86)according to the present disclosure in a curb-side or neighborhood areacabinet 88 as shown in FIG. 2, the distance between this interface andeach network device within or around the user site may be kept veryshort. Short distances, on the order of several hundred to a thousandfeet, e.g., 100 to 300 meters, can enable the technology of the presentdisclosure to operate at data rates well above 100 Mbps. Even shorterdistances, by locating the broadband multidrop local network interface86 at a demarcation point 82 of a building 80, enable operation of thetechnology of the present disclosure at proportionally higher datarates.

The embodiments of the external media shown in FIGS. 1 and 2, betweenthe local interconnect company 70 (alternatively, interconnect serviceprovider) and the demarcation point 82, are two examples of the kind ofexternal network facilities to which the broadband multidrop localnetwork of the present disclosure may be connected. As shown, thebroadband multidrop local network is readily adaptable, both as to thephysical interface and the performance interface, to high speed systemsaccessible via various forms of twisted pair, coax cable or fiber opticline, for example, depending on the interface embodied in the networktransceivers associated with or contained within the addressable networkdevices coupled to the network.

To attain such high data rates, digitally modulated analog signals areutilized as applied over a very wide frequency range and operated over acomparatively short distance on an exemplary copper wire medium. Underthese conditions, the broadband multidrop local network architecture ofthe present disclosure provides improved capability over existingtechnologies. A comparison of the maximum data rate and the bandwidthused by existing technologies and the broadband multidrop local networkarchitecture of the present disclosure is illustrated in the bar chartsof FIGS. 3 a and 3 b respectively. In FIGS. 3 a and 3 b, data rate rangein Megabits per second (Mbps) (shaded bar) is shown next to bandwidthavailable in Megahertz (MHz) relative to equivalent scales at the bottomand top horizontal axes, respectively, enabling a comparison ofbandwidth among the various technologies as well as maximum bandwidthutilization.

Referring specifically to FIG. 3 a, there is illustrated the relativebandwidth and data rate performance criteria of four conventional DSLnetwork architectures in the prior art. In the upper graph of FIG. 3 a,IDSL (Integrated services digital network Digital Subscriber Line) isshown as requiring approximately 40 kHz of bandwidth and provides acombined data rate of 144 kbps (thousand or kilobits per second) for twoB channels (64 kbps each) plus one D channel (16 kbps). For typical dataapplications, the two B channels are used to create a 128 kbps channel.IDSL is a relatively low speed technology and is used in point-to-pointapplications. IDSL can provide satisfactory point-to-point operationover a range of several miles.

ADSL (Asymmetric Digital Subscriber Line) technology operates over aband from 25 kHz to 1.1 MHz. ADSL is designed for point-to-pointapplications and provides a maximum download data rate of 8 Mbps and amaximum upload data rate of 640 kbps. ADSL technology is designed tooperate over a range of up to 18,000 feet. Typical download data ratesvary with the length of the outside plant wiring used and range from 384kbps at 18,000 feet up to 8 Mbps for distances shorter than around12,000 feet. Upload data rates can also vary with distance.

FDQAM (Frequency Diverse Quadrature Amplitude Modulation) was developedby an organization referred to as the HomePNA (Home Phoneline NetworkingAlliance). FDQAM as implemented by the HomePNA enables data rates of upto 10 Mbps within a building over a distance of up to 500 feet andfunctionality at distances of up to 1000 feet. The technology developedby the HomePNA is designed for multidrop applications within a building.However, the HomePNA technology is not designed for direct connection toa service provider network as are IDSL, ADSL, VDSL, and the broadbandmultidrop network technology of the present disclosure. The bandwidthused by the HomePNA FDQAM technology is 6 MHz, extending from 4 MHz to10 MHz. The comparatively low bandwidth and the lack of dynamic poweroutput control in HomePNA transmitters impede the ability of the HomePNAtechnology to operate at either very high data rates or over extendeddistances when compared to the broadband multidrop technology of thepresent disclosure.

VDSL (Very high-data-rate Digital Subscriber Line) technology operatesover a range of 200 kHz to 30 MHz except within the range from 4 MHz to10 MHz. The 4 MHz to 10 MHz break is to enable simultaneous operationwith HomePNA technology. The approximate 24 MHz bandwidth and high powertransmitters employed enable download data rates of 51.84 Mbps withupload data rates of 6.48 Mbps over wire lengths up to 1000 feet.Present modulation technologies used for VDSL are typically implementedwith CAP16 (Carrierless Amplitude Phase) modulation.

Referring now to FIG. 3 b, the broadband multidrop local networktechnology described in the present disclosure is not as limited inbandwidth or amplitude as the previously described technologies, thusenabling operation at much higher data rates over comparatively shortdistances in applications such as illustrated in FIG. 2. In FIG. 3 b,the bandwidth and the maximum data rate both extend continuously fromvery low values to well above 100 MHz/100 Mbps, reflecting the fullspectrum capability of the broadband multidrop local network describedherein. In contrast, the conventional, point-to-point technologies suchas IDSL, ADSL, HomePNA FDQAM, and VDSL shown in FIG. 3 a are allspecifically limited in bandwidth and amplitude in order to reduceinterference in common cable bundles. Additional restrictions are placedon the bandwidth and operating bands of HomePNA FDQAM, ADSL, and VDSLtechnologies to enable compatibility between each respective technologyand other technologies operating simultaneously on the same line. Forexample, the ADSL and HomePNA FDQAM have range limitations to enablesimultaneous operation over the same telephone line. HomePNA FDQAMoperates in a frequency range above that of ADSL in order to avoidinterference between the two technologies. In another example, ADSL maybe used to distribute data point-to-point from the service provider to abuilding and the HomePNA technology is used to distribute the datawithin the building.

Another example is seen in the range limitations of VDSL and HomePNAFDQAM. VDSL has a notch from 4 MHz to 10 MHz enabling operationsimultaneously with HomePNA FDQAM. This configuration allows VDSLtechnology to supply data from the service provider to or from abuilding via a point-to-point connection; then, the data is distributedwithin the building using a secondary network based on the HomePNA FDQAMtechnology.

In the broadband multidrop local network illustration of FIG. 2, personsskilled in the art will appreciate that adjacent wiring bundles (andassociated cross talk interference) are not present or needed from adistribution point within curb side or neighborhood area cabinet 88 overcopper wiring 76 to, within, and around a single building 80. In such asystem, the amplitude and frequency range used for modulating data canbe significantly increased over those applied in existing technologies.For example, the maximum transmission level and an upper frequency limitof 30 MHz for VDSL technologies were chosen to keep crosstalk betweenadjacent wire pairs in cables to an acceptable minimum. By removing therequirement for operation in bundled wiring, the broadband multidroplocal networks of the present disclosure can operate at its maximum datarate, bandwidth and signal transmission level constrained only by thephysical properties of the network 20 and radiated emissionslimitations. (Radiated emissions, as is well known, are established bygovernment organizations such as the FCC of the United States or the CSAof Canada.) Further, modulated RF data signals enable data to be carriedfurther at comparable data rates over a copper medium, than othertechnologies, without requiring the use of repeaters or the like.

For the example of a single tenant building, a pair of wires issufficient for carrying very high data rates using equipment thatoperates according to the teachings of the present disclosure. Formultiple tenant dwellings, however, such as apartment complexes and highrises, the data rate of the apparatus disclosed herein may need to bereduced to restrict the bandwidth and control signal levels to keepcross talk within acceptable limits for multiple user networks in closeproximity.

Because the technology of the present disclosure is designed to replaceexisting technologies, compatibility with conventional technologies isnot a requirement. The bandwidth that previously required multipletechnologies and systems that divided the frequency spectrum amongtechnologies in order to achieve full coverage can be covered by theequipment designed according to the unified technology of the presentdisclosure. Therefore, the overall data rate can be higher than otherDSL technologies, given the same physical wiring constraints. As anexample, the total VDSL bandwidth is limited to around 24 MHz, becauseof the constraints of crosstalk in bundled cable pairs and because ofthe aforementioned 4 MHz to 10 MHz break or notch to ensurecompatibility with HomePNA technology. By utilizing the Broadbandmultidrop local technology of the present disclosure in place of thecombined VDSL and HomePNA FDQAM technologies in multiple tenantdwellings, the full bandwidth extending to 30 MHz is available, as wellas the usable bandwidth above 30 MHz, thereby resulting in the potentialfor a greatly increased overall data rate. Also, removing the need forretransmission by a bridge to or from a secondary network within somebuilding installations can further increase the data rate.

A further aspect of the broadband multidrop local network of the presentdisclosure is the ability to enable the direct operation of one or morenetwork devices on the network 10 of FIG. 1 or the network 20 of FIG. 2in conjunction with one another and/or a service provider withoutrequiring a separate secondary network within a building 80. Thisaspect, plus having a common, low cost interface in each attachednetwork device, enables wide acceptance of the broadband multidrop localnetwork technology disclosed herein.

Description of a Network Interface

Referring to FIG. 4, there is illustrated one application of thebroadband multidrop local network technology of the present disclosureshowing a broadband multidrop local network interface 86 operating inconjunction with one example of a network device—a compatible telephoneset 52. This illustration is merely exemplary and is presented to showthe versatility of the technology and its potential for wide-spread use.It should be understood that many other uses of the network technologyof the present disclosure are possible as will occur to persons skilledin the art.

In the configuration of FIG. 4, IP-based telephone set 52 is used toplace and receive Voice over Internet Protocol (VoIP) calls through aservice provider via optical fiber 74, broadband multidrop local networkinterface 86, and the copper wiring 72 and 84 interconnected atDemarcation 82.

For an outgoing call, handset 512 is taken off-hook and a numericdestination address is dialed on keypad 514. The keypad numeric sequenceis collected by microprocessor 502 c of processing unit 502. The keypadnumeric sequence is transferred through keypad interface 510 through theDATA bus to microprocessor 502 c. Control of the transfer of the numericsequence is provided by programmable logic device (PLD) 502 b.Microprocessor 502 c, in turn, uses the numeric sequence received toaddress the packets to be transmitted and to establish a connection.Packets are transmitted according to well-known industry standardprotocol(s).

Once a connection is established, audio from the microphone of handset512 is amplified in amplifier stage 508 and converted to a digitalformat in codec 504. From codec 504, the digitized voice data iscollected in DSP 502 a and converted to a compressed version using acompression standard. Compression standards include, but are not limitedto, e.g., the International Telecommunications Union's standards fordata communication transmission facilities (ITU-T) such as G.711,G.723.1, G.726, and G.729a. The compressed voice data is thentransferred through PLD 502 b to microprocessor 502 c for assembly andpacketization. Program storage and temporary variable storage forperforming operations on voice data are contained in FLASH memory 506 aand SRAM 506 b of memory circuitry 506, respectively.

From Microprocessor 502 c of processing section 502, the voice datapackets are coupled to broadband multi-drop transceiver 400. Thebroadband multidrop local network interface or transceiver 400 thenprepares the packets for transmission and correspondingly modulates thesignal on an analog carrier or a plurality of carriers which traversethrough high pass filter 524 and over the broadband multidrop localnetwork consisting of twisted-pair copper wire links 84 and 72 with aninterconnection at demarcation 82. The transmitted signal then reachesbroadband multi-drop interface 86 and is selectively passed through highpass filter 530 and to a broadband multidrop local transceiver 401 ofthe broadband multidrop local network interface 86. The broadbandmulti-drop transceiver 401 then transfers digital electrical signals tothe optical fiber transceiver 520 followed by transmission to the localinterconnect company and service provider through optical fiber 74. Theuse of an optical fiber link 74 and related interface components areexemplary and could alternatively be a coaxial cable link and relatedinterface components, or the like. Data packet transmission continuesthroughout the duration of the call. In order to increase networkefficiency and reduce overall data transmission, the telephone set 52may implement a triggering software routine in DSP 502 a that requirestransmission of voice data only when words are spoken. In that case,data is not transmitted in the absence of spoken words or other audiooccurrences that do not fit the voiced triggering parameters.

For incoming calls, voice data packets arrive at broadband multi-dropinterface 86 via optical fiber link 74. Optical transceiver 520 receivesthe optical signal carrying the voice data and converts it to digitalelectrical signals. The digital electrical signals are received bytransceiver 401 and converted to voice data packets that are modulatedon a carrier or carriers that pass through high pass filter 530 andtraverse the multi-drop network wiring comprised of twisted-pair copperwire 72 and 84 interconnected by demarcation 82. The modulated carriersignals reach and selectively pass through high pass filter 524 andproceed to transceiver 400 of telephone set 52. Transceiver 400demodulates the received carrier signals and converts these to voicedata packets that are sent to microprocessor 502 c. Microprocessor 502c, in turn, depacketizes the voice data and transfers it to DSP 502 athrough PLD 502 b. DSP 502 a of processing section 502 then decompressesthe voice data and sends it to codec 504 for conversion to an electricalanalog signal. The electrical analog signal progresses to amplifier 508where its amplitude is set to a level consistent with the requirementsof the earpiece or speaker element of handset 512 where the electricalanalog signal is converted to an audible signal.

Continuing with FIG. 4, an initial notification data signal to providean indication of incoming calls is received through optical fiber 74,which is connected to broadband multidrop local network interface 86.Corresponding electrical signals reach optical fiber transceiver 520where they are converted to electrical signals and sent to transceiver401. The electrical incoming call notification signals progress fromtransceiver 401, where they are modulated onto a carrier, traversethrough high pass filter 530 and further continue through thetwisted-pair copper multi-drop network consisting of wire 72 and 84interconnected by demarcation 82. The modulated incoming callnotification signal then progresses to telephone set 52 and high passfilter 524 before reaching transceiver 400 for demodulation and transferas data packets to microprocessor 502 c. Microprocessor 502 c thenconverts the data packets to acoustic signals generated by transducer528 of a sufficient level to notify a user of an incoming call. When thehandset is taken off-hook, the voice paths are connected andconversation may commence. During conversations, voice data istransmitted and received as previously described.

It will be readily appreciated by persons skilled in the art that manyalternative embodiments of the network device 52 shown in FIG. 4 coupledwith a network interface 86 are contemplated and the compatibletelephone set 52 is not intended to be limiting. For example, the device52 of FIG. 4 may be modified by replacing the CODEC 504 and telephonehandset 512 respectively with an analog-to-digital converter and any ofmany possible analog signal sources. Thus, digitized analog signals fromany source device may be processed and interfaced to the broadbandmultidrop local network of the present disclosure.

As an optional feature, DC or low frequency AC power may be coupled tothe broadband multidrop local network from a localized source. Highpower devices such as a repeater, security camera, a microprocessor orDSP enabled telephone set, or the like may thus be powered locally andnot limited as in the DC battery available from a typical C.O. switchingsystem. Whether provided locally or off-site, the power levels providedcould be much higher than those found in typical telephone systems andadditionally may not necessarily be required to comply with existinggovernment body rules, such as those of FCC Rules, Part 68 and the CSAStandard CS-03. The application of localized power within or near abuilding containing a user site network and the provision of high-levelpower throughout building communications wiring are new requirementsnecessitated by the application of processor-based IP-communicationsequipment at user sites.

Continuing further with FIG. 4, peripheral power supply 522 of broadbandmulti-drop interface 86 derives power from an external source such as anAC or DC power feed and supplies DC current and voltage via low passfilter (LPF) 532 to the network. From the network the internal powersupply 516, in turn, distributes regulated and filtered DC voltage andcurrent to various circuits within the telephone set 52. Further, eitherof power supply 516 or power supply 522 may be configured with batterybackup capability to prevent loss of data on the network.

Operation of a Device with a Network Interface

Referring now to FIG. 5, there is illustrated a block diagram of thebroadband multidrop local network transceiver 400 (and 401) according toone embodiment of the present disclosure. Each addressable networkdevice connected to the network includes or is associated with such atransceiver 400 which interfaces with the feed line from theinterconnect company at the demarcation point or curbside unit viafiber, cable or wireline. The transceiver 400 may be similarfunctionally to an Ethernet transceiver but differs in several respectsas will be described hereinbelow. Received data signals proceed from atwisted-pair wire or other copper medium to physical interface 422.Physical interface 422 may include a connector for connecting thetransceiver 400 to the twisted pair wiring or other medium, a couplingtransformer, over-voltage protection components, and may also includecoupling capacitors for DC isolation. The physical interface 422 couplesthe data signals to a broadband multidrop local network modem 418 wherethe incoming packetized IP data signals may be demodulated. Thetransceiver 400 operates on packetized IP traffic, converting incomingor local-device-originated communications to the broadband multidroplocal network format for local distribution or, vice versa, for outgoingtraffic from the broadband multidrop local network devices. Modulationschemes employed may include multiple subcarrier modulation, carrierlessamplitude phase (CAP) modulation or discrete multitone (DMT) modulation,or a form of quadrature amplitude modulation (QAM), which are well-knownin the art.

Continuing with FIG. 5, data rate control 420, a component of thebroadband multidrop local network modem 418, is shown in a typicalapplication to enable automatic data rate control so that the data ratecan be reduced to account for line impairments while still achieving avalid data throughput; and (b) to allow for a maximum data rate to beset manually during installation by limiting the bandwidth andtransmission power level to account for cases where bundled cable pairsare used.

From the broadband multidrop local network modem 418, data packets aresent to the media access control (MAC) unit 414. The MAC unit mayinclude a data link layer, frame formatting, address assignment, and anerror correction unit 416. The data link layer, frame formatting, andaddress assignment are similar to those used in an ethernet MAC. Whilean ethernet MAC also includes error correction, the strategy employed inerror correction unit 416 includes additional elements to account forerrors encountered in a broadband multidrop local network that arecomparatively negligible in an ethernet network. Examples of such errorswould include data corruption resulting from radio frequencyinterference, signal reflections, and impulse noise caused by poweractivation and deactivation in networked devices, such as compatibletelephone sets, varying current requirements during power activation anddeactivation in signaling transitions and the like. Further, when othercompatible, similarly powered devices are used in a broadband multidroplocal network, the wiring comprising the network can also carry voltageand current necessary for powering these devices. Impulse noise iscaused when these network powered devices increase or decrease theamount of current that is being utilized. The error correction unit 416is implemented to overcome data errors encountered in a broadbandmultidrop local network. Error correction unit 416 further incorporates,among other strategies, a Cyclic Redundancy Check (CRC) and a low levelretransmission capability to facilitate handling of the data by the IPstack. Data errors in excess of those typically found in ethernetenvironments are not handled well by traditional IP stacks. Errorhandling prior to the IP layer simplifies the overall operation byenabling the use of existing ethernet standards for the bulk of the IPdata manipulation.

Continuing further with FIG. 5, data packets operated on in multimediaaccess control (MAC) 414 proceed to a carrier sense multipleaccess/carrier detect (CSMA/CD) unit 410. CSMA/CD unit 410 functionsinclude carrier sense, deferral, and collision detection 412. Collisiondetection 412 is an important aspect of the network of the presentdisclosure and helps enable a plurality of user site devices to beconnected and communicating on a broadband multidrop local network ofthe present disclosure. CSMA/CD unit 410, in turn, transmits packet datathat it has operated on to the Quality of Service (QoS) layer 406. QoSlayer 406 defines performance criteria used for data traffic managementto automate the consistent and timely throughput of real-time datapackets, such as those involved in the transfer of voice, audio, orvideo information. The QoS layer 406 includes priority control, latencycontrol, and collision resolution 408. Rapid determination of priorityof data packets, control over latency of data packets, and rapidresolution of collisions from devices accessing network 10 of FIG. 1 ornetwork 20 of FIG. 2, are combined to ensure a very high data throughputof both real-time and non real-time data in the broadband multidroplocal network of the present disclosure.

More particularly, received packet data operated on in QoS layer 406 istransferred to a computing device, such as microprocessor 402 forinterfacing between the network transceiver 400 and the addressablenetwork device. Microprocessor 402 may further provide specializedfeatures for implementation in transceiver 400. Specialized featuresimplemented in microprocessor 402 may include, but are not limited to,ITU-T standard H.323, a protocol for real-time packetized multimediatraffic on IP telephony, data encryption/decryption,packetization/depacketization, security protocol control such as IPsec,and the like. The operating software for microprocessor 402 is stored inmemory 404 which may also provide temporary storage for variables orconfiguration values used by the operating software and buffer storagefor data transfers. Microprocessor 402 further transfers data to andfrom transceiver 400 and attached devices through the data and controlinterfaces and enables the maintenance of a secure communications link,such as those using IPsec, VPN technologies, or the like. A secure linkis especially important when communicating voice, audio, video, orcritical data through the Internet, for example.

The operational functions of the network transceiver 400 may bepartitioned in various ways as will be apparent to persons skilled inthe art. As one example, the functions of media access control (MAC)unit 414, carrier sense multiple access/collision detect (CSMA/CD) unit410 and quality of service (QoS) layer 406 may be grouped togetheroperationally as a network controller for processing traffic through thenetwork transceiver 400.

Data transfer from transceiver 400 into the network enters through thedata and control interfaces of microprocessor 402 and may or may not bepacketized. If the data is not packetized, the microprocessor 402 iscapable of packetizing it. Further, if required prior to packetizing thedata, microprocessor 402 can encrypt or add security enhancements to thedata. Next, the packet data is transferred from microprocessor 402 tothe QoS layer 406 which encodes priority information into the packetdata. This priority information will be used by receiving equipment toestablish the priority of received data and to assist in controllinglatency of data within the network. A further aspect of the use of theQoS layer 406 is that not only is the QoS performed in response to QoSinformation incorporated in the data header, but it includes the abilityto specify the rated available bandwidth for each attached terminal anddevice up front, so that the user always knows that the total number ofdevices or the total bandwidth utilization requirement is also included.Such rating could be provided as a label on the device; thus the userneed only add up the ratings for all of the attached devices todetermine whether the system capacity is fully utilized. Alternatively,information about required data rates could be stored in a memorylocation in transceiver 400 to be monitored and displayed to the user ona connected computer system from an addressable location on the network.

Continuing with FIG. 5, the packet data operated on in QoS layer 406 istransferred to CSMA/CD unit 410. The CSMA/CD unit 410 determines whetheror not it is safe to transmit the packet data based on information fromthe collision detection unit 412. Packet data operated on in CSMA/CDunit 410 proceeds to the media access control 414 (MAC) layer. The MAC414 layer provides frame formatting, address assignment, and errorcorrection 416. Within the MAC 414 layer, error correction unit 416 isemployed to encode error correction information into the packet to betransmitted.

Packet data operated on in the media access control (MAC) 414 layer istransferred to the broadband multidrop local network modem 418. Thismodem 418 modulates the packet data onto a wireline analog radiofrequency signal to be transmitted employing a modulation schemeconfigured to provide packetized IP traffic on the network—in effect, apseudo spread spectrum technique. Such schemes may include multiplesubcarrier modulation, forms of quadrature amplitude modulation (QAM),carrierless amplitude phase (CAP) modulation or discrete multitone (DMT)modulation. The packet data is modulated using bandwidth and levelconstraints provided by data rate control unit 420. From broadbandmulti-drop DSL modem 418 the packet data flow proceeds through physicalinterface 422 and on to the twisted pair wire or other copper medium.

Referring now to FIG. 7 there is illustrated one embodiment of theprocessing provided in the QoS layer 406 of FIG. 5. The subroutine forprocessing QoS begins at block 701 and advances to a decision block 703to determine whether or not data has been received from the line by thephysical interface 422 of the network transceiver 400 shown in FIG. 5.If data is received, the flow proceeds to block 705 which represents thesuccessful progress of the data through other functional blocks of thetransceiver 400, namely, the broadband multidrop modem 418, media accesscontrol 414 and the CSMA/CD block 410. In the next step 707 in QoS layer406, the processing checks the QoS value in the data header, updates aQoS table (not shown) in memory 404 using microprocessor 402, the QoSvalue in the QoS table indicating current line traffic QoS levels.Subsequently, in step 709, the data address is checked and, in decisionstep 711, it is determined whether the data is for this device oranother device. If it is for “this” device the flow proceeds to block713 to transfer data from QoS (control) layer 406 to microprocessor 402and thence to a data circuit coupled to the data interface ofmicroprocessor 402. After the transfer of the data in step 713, thesubroutine returns in step 715.

Continuing with FIG. 7, if either the data is not received from the lineby physical interface 422 in step 703 or the data is not for “this”device as determined in step 711, the flow proceeds to decision step 717to determine whether the data is to be transmitted to the line. If not,the subroutine returns at a Return block 735; but if the data is to betransmitted to the line, the flow proceeds to block 719 to check the QoStable in memory 404, using microprocessor 402 to determine line trafficQoS levels in QoS (control) layer 406. Then, in decision step 721, adetermination is made whether traffic of higher real-time priority is onthe line and, if not, the data proceeds in step 727 through the datainterface of microprocessor 402 and into the microprocessor 402 forprocessing through CSMA/CD 410 and media access control 414. Followingthe processing in media access control 414, the data in step 729 ismodulated onto the line by broadband multi-drop modem 418 though thephysical interface 422 after which the subroutine returns, in step 731.If, in step 721, traffic of higher real-time priority is on the line,then the flow proceeds along the “Yes” path to step 723 to check for themaximum time allotment for delay of the present data to be transmitted,the check being performed in the QoS latency control section 408. Next,the system determines whether the maximum delay time has occurred and,if so, the data is processed in accordance with step 727; otherwise theprocess flow returns via step 733.

FIG. 8 illustrates an exemplary simplified diagram of the networkdescribed hereinabove. In the embodiment of FIG. 8, a network mesh 802is illustrated that provides the communication path for all packetsgenerated by any node on the network. There are illustrated fourdevices, network device 804, network device 806, network device 808 andnetwork device 810 labeled Device 0, Device 1, Device 2 and Device 3,respectively. Each of these devices 804 through 810 is operable togenerate packets of data that are placed onto the network mesh 802.These packets have a protocol that is recognized by all other networkdevices, it being understood that only one data packet can betransmitted onto the network mesh 802 at any one time. Any type ofprotocol can be utilized. Therefore, each of the network devices 804through 810 must have some type of collision avoidance associatedtherewith, i.e., when one network device has access to the network mesh802, the other network devices do not transmit data packets to thenetwork mesh 802. Of course, transmission of data packets onto thenetwork mesh 802 by multiple devices in an orderly manner isconventional. However, in most data transmission environments, data istransmitted to the network mesh 802 on an “available” basis, i.e., ifmultiple devices exist on the network mesh 802, then the rate at which agiven network device can transmit packets is reduced in that alltransmitting devices are sharing the bandwidth of the network mesh 802.This results in a slower data throughput for any given device. This isbasically referred to as “high traffic” on any type of network mesh.

As an example, consider a standard Ethernet system that has a defineddata rate for the network mesh. A data packet will be assembled by anygiven network device, which data packet can be transmitted at up to themaximum data rate of the network mesh. However, if there are a largenumber of devices on the network mesh, then the number of data packetsby any one device will be reduced, whereas the total number of datapackets on the network mesh by all the devices can be transmitted at themaximum data rate of the bus. If there are real time applicationsassociated with any one of the network devices, then this provides asignificant disadvantage to a given network device in that some datawill merely be lost. An example of this would be a streaming videoapplication wherein all of the data packets associated with a givenframe of video information must be transmitted within a given time. If,for some reason due to traffic, that data will not transmit during theframe, it would merely be lost if received later, as it will beassociated with a frame that has already been displayed—hence it will bediscarded.

In the present disclosure, each of the network devices 804 through 810has associated therewith, in one embodiment, a defined portion of thedata traffic capabilities of the network mesh 802. For example, ifDevice 0, network device 804, when operating at its full data rate,required forty percent of the available data traffic capabilities toensure that all data packets required to be transmitted were in facttransmitted and received, this amount of the data traffic capabilitieswould be allocated to or reserved for that device. This orientationwould be similar for the remaining devices 806 through 810, i.e, eachwould have a proportionate amount of the data traffic capabilitiesreserved in accordance with the requirements of each device. This isillustrated in FIG. 9.

In FIG. 9, there is provided a diagram of the data traffic capabilitythat is associated with the network mesh 802. There is provided a firstportion of the data traffic capability 902 that is associated withdevice 806, labeled “D1.” This is the portion that will be provided tothe device 806 which has been predetermined to require this amount ofthe data traffic capability, i.e., it must be able to transmit a certainnumber of data packets within a certain period of time. A second portion906 is provided associated with device 808, labeled “D2” with a thirdportion 908 associated with device 810 labeled “D3” and a fourth portion910 labeled “D0” associated with the device 804. In this example, theportions 902, 906, 908 and 910 do not utilize the entire data trafficcapability. There is a section 912 that provides an additional availableportion that can be occupied by another device. However, each of thedevices 804 through 810 is guaranteed a reserved portion of the datatraffic capability. If another device were added to this system thatrequired, during operation thereof, a portion of the data trafficcapability on the mesh 802 that exceeded the portion 912, that being theremaining unreserved portion 912, it would be denied access to thenetwork mesh 802. This would be the case in this embodiment even thoughnone of the devices 804 through 810 were actually operating on thenetwork mesh 802. Even though no data packets are being transmitted, itis the reservation of the data traffic capability that defines whether adevice can have access to the mesh 802 and constitute an availabledevice on the network. This embodiment will be expanded upon hereinbelowwith various priority levels. However, in this embodiment, each devicehas the same priority level and the existence of other devices has nobearing on the ability of any given device to transmit at its fullpacket rate on the network mesh 802.

In an alternate embodiment illustrated in FIG. 10, the data trafficcapability is divided up into a first portion 1002 associated with thenetwork device 806 labeled “D1,” a second portion 1004 is associatedwith network device 808 labeled “D2,” and a third portion 1006 isassociated with the network device 810, labeled “D3.” The network device804 labeled “D0” cannot be added to the network, due to the fact that ithas a data traffic capability requirement depicted as a Section 1008that is in excess of the previously reserved data traffic capability,the data traffic capability being totally reserved for use by devices806 through 810. Again, even if the devices 806 through 810 are allinactive, access is still denied to device 804. As will be describedhereinbelow, access can be determined by a user examining the datatraffic capability requirements of a given device via a label or thesuch with knowledge of the devices already existing on the network andknowledge of the total data traffic capability that can be accommodatedby the network. In that situation, the user would just refrain fromadding a device that would exceed the reserved data traffic capability,thus ensuring that all devices would operate at full packet rate.

Referring now to FIG. 11, there is illustrated a flowchart depicting theoperation of adding a device to the network, from the network deviceperspective. This is initiated at a block 1102 and then proceeds to afunction block 1104 wherein the address and data traffic requirementsare sent to the network from the device. Typically, this will occur withthe requesting device transmitting to the network a signal in the formof a data packet indicating its presence on the network as a request foraccess and/or reserving the required portion of the data trafficcapability of the network. This data packet will have the address of therequesting device seeking access to the network, in addition toinformation about the requesting device, i.e., data trafficrequirements, priority levels, etc. There will be at least one device onthe network that will recognize this as an “I am here” data packet anddetermine if there is any unreserved data traffic capability on thenetwork to allow access. This decision will be made at a decision block1106. If there is no available unreserved data traffic capability, adata packet will be sent back to the requesting device to deny access,as indicated by flow along a “No” path to a block 1108 to deny access.If the data traffic capability is available, the program flows along a“Yes” path to a function block 1110 to allow access and then to afunction block 1112 wherein a local table of network devices will bebuilt at the device. This block 1112 is an optional step which allowsthe newly accessing device to be provided with information as to whichdevices are presently on the network, this being for the purpose ofcommunicating with those devices. However, it can be that no actualknowledge of devices present on the network is required. For example, ifa network IP-based telephone were attached to the network and attemptedto contact another network device that was not granted access throughits address known from other sources, it would just be providedinformation that the network device cannot be reached. After access andbuilding of the local table of network devices is complete, the programwill flow to a Return block 1114.

Referring now to FIG. 12, there is illustrated a flowchart depicting theoperation of determining availability on the network. The program isinitiated at a Start block 1202 and then flows to a decision block 1204.There will be at least one device on the network that will be assignedthe task of responding to access inquiries from a new device. If thedecision block 1204 determines that a new device is acquiring access, itwill flow along the “Yes” path to a decision block 1206 to determine ifthe total reserved data traffic capability (DTC) plus the DTC requiredby the new device is greater than the unreserved DTC on the network. Ifso, the program will flow to a function block 1208 along a “Yes” path totransmit back to the requesting device a data packet indicating thataccess is denied. However, if excess DTC is available, the program willflow along an “No” path to a function block 1210 to accept the deviceand transmit a packet to the requesting device indicating that there isunreserved DTC available. Although not illustrated, during adetermination of unreserved DTC, the device provided the task ofdetermining unreserved DTC has the ability to actually poll the otherdevices that are currently indicated as having reserved DTC on thenetwork. If one of these devices has been disconnected from the network,then it will be removed from an internal table that is associated withthe access determining device. Once the determination has been made thatunreserved DTC is available and the data packet indicating such has beentransmitted to the new requesting device, then the table will be updatedand this table information can then be propagated to all the otherdevices on the network, as indicated by a function block 1212. However,it is not necessary that all of the devices be provided this informationdepending upon the application. It is important that there be somecentral location that has knowledge of this information and can providethe control over the access to the network. After the table has beenupdated, the program flows to a Return block 1214.

Referring now to FIG. 13, there is illustrated a simplified diagram ofhow the information is distributed over the network. In thisillustration, there is shown a plurality of network devices 1302 labeledD0, D1, . . . DN. Each of these network devices 1302 has associatedtherewith a network access table 1304 which has associated therewithinformation as to network access. In one embodiment, a priority will beestablished wherein the first device to access the mesh 802 will beassigned as the access controller. It will continually or periodicallypoll each of the devices to determine their continued existence on thenetwork. Each of the devices not having the access determination taskwill exist in a mode that will require polling by the accessdetermination device to have occurred on a periodic basis. If, for somereason, the accessing determining device is removed from the network,then the remaining devices will become aware of this and the next deviceto have accessed the network mesh 802 after the original accessdetermining device had accessed the network will then take over the taskof the access determining device and all of the other devices will havetheir priorities in that chain altered, such that each of the tables1304 has contained therein the access priority thereof. However, thereare many different ways to assign the task to any given one of thenetwork devices 1302. Further, all that is required is that one of thenetwork devices reply to a new device accessing the network to make adetermination as to whether any portion of the DTC is available andwhether that portion is sufficient for the requesting device.

Referring now to FIG. 14, there is illustrated an alternative embodimentto that of FIG. 13. In this embodiment, there are no tables provided inassociation with each of the network devices 1302. Rather, there isprovided a controller 1402 on the network that has associated therewitha table 1406. This table 1406 contains all of the network information asto which devices are on the network mesh and makes all determination asto network accessability, i.e., the controller 1402 has knowledge of thereserved bandwidth for all devices and knowledge of each device's datatraffic requirements. It can determine, when receiving a request from adevice to gain access to the network, whether there is any unreservedbandwidth.

Referring now to FIG. 15, there is illustrated a flowchart depicting analternate embodiment of the operation of handling a request for access.This is initiated at a Start block 1502 and then proceeds to a decisionblock 1504 to determine if a device is requesting access. If so, theprogram flows to function block 1506 to receive both address andbandwidth requirements as described hereinabove. Determination is thenmade at a decision block 1508 as to whether the additional data trafficrequirements for the new device will exceed the available unreservedbandwidth. In this embodiment, if the unreserved bandwidth has beenexceeded, the program will flow along a “Yes” path to decision block1510 to determine if the data traffic capability (DTC) can be increased.This is a mode wherein an Internet Provider can be contacted by thesystem to increase the bandwidth of the network. If so, the program willflow along a “Yes” path to a function block 1512 and then return back tothe input of decision block 1508. However, if bandwidth cannot beincreased, the program will flow along a “No” path to a function block1514 to deny access. In this mode, where bandwidth can be increased, itis possible that the bandwidth availability is a function is cost. Itmay be that a new application associated with the new device has datatraffic requirements well in excess of that available. As such, therecan be a provision available to the user that will allow the bandwidthto be increased when a new service provision is implemented, i.e., adevice with a higher data traffic requirement is added to the system.This could be automatic wherein a controller would request from acentral system, i.e., in Internet Provider, additional bandwidth. Thiscould be then reflected in the billing information for the user. Ofcourse, this bandwidth could actually be temporary and could be loweredat a later time when the device was removed. Additionally, the deviceson the network must be able to increase their data rate so as todecrease the time duration of a packet.

When it has been determined that the device can be added due to theavailability of data traffic, the program will flow as notedhereinabove, to a function block 1520 to allow access and then to afunction block 1522 wherein a table will be updated with the devicesthat have been granted access and the data traffic requirementstherefor. The program then flows to an End block 1524.

Referring now to FIG. 16, there is illustrated a flowchart depicting analternate embodiment for granting access to the network. This program isinitiated at a function block 1602 and then proceeds to a decision block1604 to determine if a device is attempting to access a network. If so,the program flows along a “Yes” path to a function block 1608 to checkthe table for available data traffic capability (DTC) and then to adecision block 1610 to determine the available DTC, as describedhereinabove. There are two different embodiments illustrated for thecondition wherein the currently available DTC is less than is requiredfor the addition of a new device. In the first embodiment, the programwill flow along an “N1” path to a function block 1612 to requestadditional bandwidth. This is similar to the embodiment of FIG. 15. Theprogram merely requests the bandwidth and then waits for the bandwidthto be increased. This program will flow along a path to a timeout block1614 which will allow flow of the program to return to the input tofunction block 1608. This will continue until the bandwidth has beenprovided or, if a certain time has elapsed, the program will flow fromthe timeout block 1614 to a function block 1618 to deny access, asdescribed hereinabove. In an alternate embodiment, the lack of availableDTC will result in the program flowing along an “N2” path to a decisionblock 1620 to determine priority. In this embodiment, each device isprovided a priority based upon the class of service, i.e., real timeapplications such as video streaming will have higher priority than atelephone, for example. The access table will be checked for priority todetermine if there is a lower priority network device on the system. Ifnot, the program will flow along the “No” path to a function block 1622wherein access will be denied until devices with higher priority are notaccessing the mesh. However, if it is determined that the currentlyrequesting device is a higher priority than another device on thesystem, the program will flow along a “Yes” path to a function block1624 wherein priority will be asserted, and then back to the input offunction block 1608. When priority is asserted, the network device thatdetermines access will send a request to the lower priority device thatis to be disconnected in that it no longer has access to the network andit will be removed. The program will then flow from the block 1610 whereit has now been determined that unreserved DTC is available and therequesting device can be added, to a function block 1626 to update thepriority access table with both access information and priorityinformation. The program will then flow to a function block 1628 toallow access to the network and then to a Return block 1630.

Referring now to FIG. 17, there is illustrated a flowchart depicting theoperation of adding a device to the network. As noted hereinabove, whenan additional device requires access to the network, it must be able toreserve a portion of the available data transfer capabilities of thenetwork. Either there is a sufficient amount of data transfer capabilitythat is unreserved and which is equal to or less than that required bythe requesting device, or the requesting device has a priority thatexceeds that of one of the already attached network devices, and thatnetwork device will be taken off of the network to provide room for therequesting device.

The flowchart is initiated at a Start block 1702 and then proceeds to adecision block 1704 to determine if an access request is received. Inone aspect of the present disclosed embodiment, any requesting devicewill transmit to the network a request that will be recognized by one ormore of the devices already attached to the network. Once this device isrecognized, the program flows along the “Yes” path to a function block1706 to halt all transmission on the network from all of the attacheddevices. (“Attached” in this context indicates those devices that havebeen allowed access to the network and not the actual “physical”attachment, as a device may be physically attached, but not allowedaccess and, therefore, not “attached.”) The program then proceeds to afunction block 1708 in order to test all devices on the network toensure that the new device can fit within the unreserved data transfercapabilities of the network at the rated data transfer rate associatedwith the network. If the data rate for the device to be added alters theoverall date rate of the network as to the requirement for the presentlyattached network devices, due to the potential addition of the newnetwork device, this will then change the data transfer capability ofthe network. For example, if a slower device is added to the network,then it is possible that some of the currently attached network deviceswill be required to transmit at a slower data rate. Therefore, at adecision block 1710, a determination will be made as whether the datatransfer rate has increased or decreased and whether the data transfercapability (DTC) of the network has specifically increased or decreased.If so, then the program will flow along the “Yes” path from decisionblock 1710 to a function block 1712 to set the total DTC to the newlydetermined total DTC. The reserved portion thereof will also have to berecalculated. If not, the program will flow along the “No” path fromdecision block 1710 to a decision block 1714. Decision block 1714determines whether the reserved DTC plus the data traffic requirementsof the new device will be greater than that of the total DTC of thetotal network. If yes, then the new device will be denied access, at afunction block 1716, and then the data transfer rate or unreserved DTCwill be reset to the original DTC value, as indicated by a functionblock 1718. However, if the new device does not exceed the unreserveddata transfer capability, then the program will flow to a function block1720 to propagate a new table to all the other devices and then to afunction block 1722 wherein the network will be “unhalted” to allowcommunication over the bus by all of the attached network devices. Theprogram then flows to a Return block 1724.

Referring now to FIG. 18, there is illustrated a flowchart for the testoperation. In the test operation, each device determines the data ratethat can be transmitted to each other device in the network. It may bethat, for example, device A on the network can transmit to device B atone data rate, but device B can only transmit at a lower data rate todevice C, and device A can transmit to device C at even a different datarate. The lowest data rate between devices must be the data rate that isset for the overall network in the disclosed embodiment. (However, it isnoted that devices of differing data rates could be accommodated on thenetwork, as long as the data transfer capabilities of the network can bedetermined to accommodate these different data rate devices.) Therefore,each device must test its ability to transfer data at a particulartransfer rate to all other devices on the network to which it couldpotentially transfer data such that an accurate determination of thetotal data transfer capabilities of the network at that data rate can bemade and then a determination as to whether all of the currentlyattached network devices plus the addition of the new device can beaccommodated. For example, if a new device were to be added to thenetwork and it had a lower data rate than associated with a presentconfiguration, it may be that the network operating at that lower datarate would have the data transfer capabilities changed such that itwould not even accommodate the currently attached devices in the presentconfiguration, even without the addition of the new device.

The program is initiated at a block 1802 and then proceeds to a functionblock 1804 to set the value of Next Device to the value of “0,” and thento a function block 1805 to set the data rate at the default data rate,i.e., typically the lowest data rate The program then flows to afunction block 1806 to test the transfer data rate from the CurrentDevice to the Next Device with selected data rate. The program thenflows to a decision block 1808 to test the transfer capabilities betweendevices at this data rate. If it passes, this indicates that datapackets can be transferred at this data rate and the data rate will beincremented, as indicated by function block 1810 along the “Yes” path,which flows back to the input of function block 1806 to again test thedata transfer rate at this incremented data rate. When it is determinedthat the data transfer rate is too high, the program will flow along the“No” path to a function block 1812 to set the data rate to the lastvalue prior to the failure. The program then flows to a function block1814 to store this value in a temporary table and then to a decisionblock 1816.

At decision block 1816, a determination is made as to whether all thedevices have been tested which are attached to the network and which canbe communicated with by the current device. If the current test cycle isthat associated with the last device, the program will flow along the“No” path to increment the value of Next Device at a function block 1818then the program flows to the input of function block 1806 to again testthe Current Device transfer rate to this Next Device. When all thedevices have been tested, the program will flow along the “Yes” path ofdecision block 1816 to a function block 1820 to transmit the temporarytable for this device to the master. Of course, the current device mayactually be the master and this will just require a transfer from onelocation in memory to another. The program will then flow to a Returnblock 1822.

Referring now to FIG. 19, there is illustrated a flowchart for themaster control operation of the testing of the devices. The program isinitiated at a block 1902 and then proceeds to a decision block 1904 todetermine if the updated table has been received from a unit that isbeing tested. If so, the program will flow along a “Yes” path to afunction block 1906 wherein the table will be updated. The program thenflows to function block 1908 to determine if the last device hasperformed its network test, it being noted that each device on thenetwork is required to test its capability of communicating with otherdevices. If not, the program will flow along an “No” path to a functionblock 1910 to initiate the test at the next sequential network deviceand then flows back to the input of decision block 1904 to await receiptof the table after that next sequential network device completes itstest. Once the last device has completed its test, the program will flowfrom the decision block 1908 along the “Yes” path thereof to a functionblock 1912 to generate a master table which is a table that will then beconverted to the master table if it has been determined that addition ofa new device will not exceed the total data rate transfer capabilitiesand then this master table will be propagated, as indicated hereinabovein FIG. 17 with respect to function block 1720. The program will thenflow to a Return block 1914.

SUMMARY

To summarize, there has been disclosed a broadband multidrop localnetwork architecture for use in intercoupling multimedia traffic to andfrom a wide variety of addressable network devices. Each network devicemay be coupled via a network interface or broadband transceiver to asingle wireline coupled to an external broadband communication service.Such communication service may be provided, e.g., via fiber optic linkto a curbside terminal by an interconnection company, without requiringa complete secondary network and the associated equipment such asmodems, routers, converters, hubs, switches, etc. The full data trafficcapability at the full bandwidth achievable with relatively short runs(e.g., on the order of 100 meters) of twisted pair copper wire may beutilized when all traffic for all of the participating network devicesis packetized on a wired medium for distribution thereon without thebandwidth, point-to-point, or data rate restrictions associated withconventional individual DSL (digital subscriber line) or similarservices. In effect, the useable spectrum that exists on the broadbandmultidrop local network as disclosed hereinabove is a closed spectrum;that is, the entire bandwidth technically feasible on a twisted-pairmedium over these relatively short distances is dedicated to thebroadband communication capability implemented in each local networksuch that total data rates, with present standards and technologies, ofat least 100 Mbps, and beyond to over 500 Mbps at reasonable distances,are available for each local network transferring data packets at themaximum packet rate of all network devices attachable thereto even whenall of the network devices are transmitting. Each network device(computers, peripherals, telecommunications equipment, security systems,broadcast audio and video, to name just a few) may be assigned abandwidth or packet data rate rating such that its use on the networkappropriates a required portion of the total available data trafficcapabilities of the network when in use and the user knows immediatelywhat portion of his/her network capacity is being utilized.

OTHER EMBODIMENTS

Although the broadband multidrop local network technology of the presentdisclosure has been described in detail with respect to specificembodiments thereof, it should be understood that various changes,substitutions and alterations can be made therein without departing fromthe spirit and scope of the invention as defined by the appended claims.For example, any modulation scheme besides the multiple subcarriermodulation scheme described hereinabove may be used in the variousembodiments of the present disclosure to provide the broadbandpacketized IP data on the wired bus. Further, it is contemplated that insome applications wireless interfaces via hubs or bridges or othernetwork equipment may be connected or otherwise coupled to the wired busto provide enhanced versatility. For example, a user's PC could becoupled to the wired local network of the present disclosure yet bemoved around as the user need warrants.

1. An interface transceiver for coupling an addressable network deviceto a multi-drop local network, comprising: a modem, coupled via aphysical interface to said multi-drop local network, for demodulatingincoming packetized data from said network and modulating data outputfrom said addressable network device to form packetized data to saidmulti-drop local network; and a network controller, coupled between saidmodem and a communication interface with said addressable networkdevice, for performing error correction and quality of service (QoS)affecting data traffic through said transceiver.
 2. The interface ofclaim 1, wherein said modem is a broadband modem configured to performbroadband modulation methods for modulating and demodulating saidpacketized data.
 3. The interface of claim 2, wherein said broadbandmodulation methods are selected from the group consisting of multiplesubcarrier modulation, carrierless amplitude phase (CAP) modulation,discrete multitone (DMT) modulation, quadrature amplitude modulation(QAM), and orthogonal frequency division multiplexing (OFDM).
 4. Theinterface of claim 1, wherein said network controller is amicroprocessor.
 5. The interface of claim 1, wherein said networkcontroller is adapted for performing carrier sense multiple access withcollision detection (CSMA/CD).
 6. The interface of claim 1, furthercomprising a communication processor, disposed integrally with saidcommunication interface with said addressable network device andconfigured to process data traffic between said network controller andsaid addressable network device.
 7. A multi-drop network for coupling anumber of addressable network devices, comprising: a first addressabledevice comprising a broadband modem and a network controller, whereinsaid broadband modem is coupled to a bus formed by a broadband networkand configured to demodulate packetized data incoming from saidbroadband network and to modulate packetized data for output to saidbroadband network, and wherein said network controller is configured toperform error correction and quality of service (QoS) affecting datatraffic through said broadband modem; and a second addressable devicecomprising a broadband modem and a network controller, wherein saidbroadband modem is coupled to said bus and configured to demodulatepacketized data incoming from said broadband network and to modulatepacketized data for output to said broadband network, and wherein saidnetwork controller is configured to perform error correction and qualityof service (QoS) affecting data traffic through said broadband modem,wherein said first and second addressable devices are adapted to becoupled to a broadband multi-drop interface via said bus formed by saidbroadband network.
 8. The multi-drop network of claim 7, wherein saidbroadband multi-drop interface comprises: a first physical interface forconnecting said bus to a broadband multi-drop transceiver; wherein saidbroadband multi-drop transceiver is configured to transfer digitalelectrical signals between said first physical interface and an outsideplant communication transceiver; and a second physical interface forconnecting said outside plant communication transceiver to an outsideplant communication medium, and wherein said outside plant communicationtransceiver is configured to transmit data to a local interconnectcompany via said outside plant communication medium and receive datafrom said local interconnect company via said outside plantcommunication medium.
 9. The broadband multi-drop interface of claim 8,wherein said outside plant communication medium is a coaxial wirelineand said outside plant communication transceiver is a coaxialtransceiver.
 10. The broadband multi-drop interface of claim 8, whereinsaid outside plant communication medium is an optical fiber and saidoutside plant communication transceiver is an optical fiber transceiver.11. The multi-drop network of claim 7, wherein said first addressabledevice is configured to transmit said modulated data output via a firsttransmit frequency and said second addressable device is configured totransmit said modulated data output via a second transmit frequency. 12.The multi-drop network of claim 7, wherein said first addressable deviceis one of a telephone, television, television receiver, televisionset-top box, fiber-to-the home television receiver, cable televisionreceiver, thermostat, utility metering equipment, high fidelity audioequipment, DVD device, VCR device, security camera, facsimile machineappliance, computer, and computer television reception card.
 13. Themulti-drop network of claim 7, wherein said first addressable device isadapted to connect to a broadband wireline local network.
 14. Themulti-drop network of claim 7, wherein said first addressable device isadapted to connect to an optical fiber local network.
 15. A method forcoupling an addressable network device via a physical interface to amulti-drop network, the method comprising the steps of: receiving anincoming broadband packetized data from a communication bus;demodulating the received broadband packetized data received from thecommunication bus; modulating a data output to form a broadbandpacketized data for broadcast to the communication bus; performing errorcorrection and quality of service (QoS) affecting data traffic; andprocessing data traffic between the communication bus and theaddressable network device.
 16. The method of claim 15, wherein thesteps modulating and demodulating of the packetized data furthercomprises selecting a modulation from the group consisting of multiplesubcarrier modulation, carrierless amplitude phase (CAP) modulation,discrete multitone (DMT) modulation, quadrature amplitude modulation(QAM), and orthogonal frequency division multiplexing (OFDM).
 17. Abroadband multi-drop interface for coupling a multi-drop network to alocal interconnect company, comprising a first connection configured toconnect to an outside plant communication medium; a second connectionconfigured to connect to a broadband multi-drop network; a broadbandmulti-drop transceiver adapted to transfer digital electrical signalsbetween said second connection and an outside plant communicationtransceiver; and said outside plant communication transceiver configuredto transmit data to said local interconnect company via said firstconnection and receive data from said local interconnect company viasaid first connection.
 18. The broadband multi-drop interface of claim17, wherein said outside plant communication medium is a coaxialwireline and said outside plant communication transceiver is a coaxialtransceiver.
 19. The broadband multi-drop interface of claim 17, whereinsaid outside plant communication medium is an optical fiber plant andsaid outside plant communication transceiver is an optical fibertransceiver.
 20. The broadband multi-drop interface of claim 17, whereinsaid multi-drop interface is configured to perform collision detectionto minimize collisions between a modulated packetized data output by afirst addressable device on said multi-drop network with modulatedpacketized data output by a second addressable device on said multi-dropnetwork.
 21. The broadband multi-drop interface of claim 17, whereinsaid second connection is configured to connect to a wirelinecommunication medium.
 22. The broadband multi-drop interface of claim17, wherein said second connection is configured to connect to anoptical fiber communication medium.
 23. The broadband multi-dropinterface of claim 14, further comprising a controller for performingQuality of Service (QoS).